96 F-superduty 7.5, E40D
241K miles
I am noticing a slight misfire when idling, and sometimes under a load, almost like pinging. I have just replaced some horrible plugs, wires, and cap. I have no CEL, and no codes with a reader. The smog pump has been bypassed and the cat is removed and replaced with a pipe, and straight piped back. The misfire causes a slight rumble. What should I look for, or is this normal wit a motor with this many miles? She has plenty of power, as I frequently tow 8000 pounds with it. I get about 8 mpgs, which I understand is normal. Thanks in advance.
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I thought you had your issue(s) resolved https://www.ford-trucks.com/forums/1...gher-rpms.html

 

Yes, mostly. Or so I thought. Truck it's a night and day difference from before, so I decided to start a new thread. This is more of an annoyance than a performance issue. Not sure if I even want to chase this problem. I will check my plugs after a few 100 miles to see what they look like.

 

What is a rumble?

 

Rumble:
motor jolts one way or another out of balance, possible from a misfire. Can hear it in the exhaust too, instead of blub blub blub it goes blub blub glub gnawadimean?

I'll get a video and post it